Hinge fitting for adjustable backrest

ABSTRACT

A hinge fitting for automobile vehicle seat in which two parts are pivoted together, comprising a recessed body or a peripheral rim of the part and a latch member in the form of a rotatable circular disc received in the body recess or in the rim. The inner peripheral wall of the recess or the internal face of the rim locates and provides a bearing for the latch member which is peripherally toothed for latching engagement with a detent. The detent engages the latch member and acts to retain the latter in the latching position.

United States Patent Yoshimura Sept. 2, 1975 HINGE FITTING FOR ADJUSTABLE 3.840.268 10/1974 Johndrow ct al. 297/367 BACKREST v 3,866,270 2/1975 Suzuki 16/146 Inventor: Noboru Yoshimura, Toyota, Japan Assignee: Aisin Seiki Kabushiki Kaisha,

Kariya, Japan Filed: Mar. 26, 1974 Appl. No.: 455,029

[30] Foreign Application Priority Data Mar. 29, [973' Japan 48-35922 Mar. 30, l973 Japan 48-36997 [52] US. Cl 297/367; 16/146 [51] Int. Cl. A47C 1/00 [58] Field of Search 297/367-369; 16/146 [56] References Cited UNITED STATES PATENTS 3.051526 8/1962 Werner ct al 297/367 Primary Examiner-James C. Mitchell Attorney, Agent, or Firm-Waters, Schwartz & Nissen [57] ABSTRACT A hinge fitting for automobile vehicle seat in which two parts are pivoted together, comprising a recessed body or a peripheral rim of the part and a latch-member in the form of a rotatable circular disc received in the body recess or in the rim. The inner peripheral wall of the recess or the internal face of the rim lo cates and provides a bearing for the latch member which is peripherally toothed for latching engagement with a detent. The detent engages the latch member and acts to retain the latter in the latching position.

9 Claims, 9 Drawing Figures PATENTED 3E? 75 SHEET 1 OF 3 FIG. I

.29 I I I illll- HINGE FITTING FOR ADJUSTABLE BACKREST BACKGROUND OF THE INVENTION The present invention relates to seats having a back and a seat frame and relates to a hinge fitting for pivotally connecting the back to the seat frame, particularly of an automobile vehicle, and more particularly to a releasable locking device combined with such a fitting for adjusting the degree of inclination of the back rest through an angle of very fine or large magnitude relative to the seat.

In fittings of this type, the possibility always exists of ruining the mechanism because the shock resulting from the sudden stopping of the forward travel of the vehicle as by collision, thereby causing a passenger in the rear passenger seat of the vehicle to strike the back rest of the seat under the influence of considerable inertial force, and thereby further causing the passenger to be thrown forwardly out of the seat. In order to safeguard the device against excessive stress being exerted by such overloads and to prevent the occupant from being thrown forwardly out of his seat, the mechanism must be sufficiently strong to resist angular movement of the back rest caused by the occupant in the rear passenger seat.

Further, it is a requirement for the fitting to permit adjustment of the degree of inclination of the back rest through an angle of very fine magnitude relative to the scat.

While various means have been previously employed for meeting such requirements, none appear to have proven to be entirely satisfactory.

SUMMARY OF THE INVENTION A principal object of the present invention is to provide a joint fitting for adjustable back rests on vehicle seats which are of simple construction and nevertheless exhibit excellent resistance against damage under operational conditions.

Another object of the invention is to provide a joint fitting which permits adjustment of the degree of inclination of the back rest through selected angles relative to the seat.

Thus, in the disclosed embodiment, there are comprised, in combination, a first arm for fastening to the seat portion and, a second arm pivoted to the first arm to form a two part hinge fitting, a recessed body and a latch member in the form of a rotatable circular disc received in the body recess with the inner peripheral surface of the recess locating and providing a bearing for the latch member which is radially notched for rotational driven engagement with the second said arm and formed with a series of peripheral teeth for engagement by detent means which act to retain the latch member in the latched position. The latch member may additionally be formed with a central axial projection on the one side thereof and the body is correspondingly formed with a hole to rotatably receive the central projection so that a bearing for the latch member is normally provided by the hole, while the periphery of the latch member is slightly spaced from the surface of the recess. This provision is intended to preserve the surface of the recess of the body for use as a bearing for the latch member in case of damage or destruction of the axial projection such as may be caused by striking of the back rest by the passenger.

The firstarm may be integrally formed with a peripheral rim to provide a bearing for the latch member in place of the recessed body. At least part of the rim so faces the peripheral surface of the latch member in slightly spaced relation thereto that another bearing may be provided by the latch member which engages the internal surface of the rim in case of the destruction or damage of the projection of the latch member.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:

FIG. 1 shows a side view of a hinge fitting con structed according to one embodiment of the inventron;

FIG. 2 is a cross section taken along the line IIII of FIG. 1;

FIG. 3 is a cross section taken along the line IIIIII of FIG. 1;

FIG. 4 is a diagrammatic view showing function of the hinge fitting of FIG. I;

FIG. 5 is a view similar to that of FIG. 1 and showing another embodiment of the invention;

FIG. 6 is a cross section taken along the line VIVI of FIG. 5;

FIG. 7 is a view similar to that of FIG. 1 and showing still another embodiment of the invention;

FIG. 8 is .a cross section taken along the line VIII- V III of FIG. 7;

FIG. 9 is a cross section taken along the line IX-IX of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more specifically to FIG. 1 thereof, it will be seen that the two part hinge fitting according to the present invention comprises a first arm 1 fixedly fastened to a seat 3 of a vehicle seat, partially shown, and a tiltable second arm 2 fastened to a back rest 4, likewise partially shown in heavy lines while in generally a normal position. The arm I is intended to be secured to the seat 3 by means of screws which are inserted into bores 5 while the arm 2 is intended to be secured to the back rest 4 by means of screws which are inserted into bores 6. The arm 2 is pivotally connected to the arm 1 by a pin 7 on the arm 1 providing a swivel axis for tilting the back rest as will become more clear as the description proceeds.

Means, to be hereinafter described, are provided for retaining the back rest in a tilted position, as desired. To such end, there is provided a recessed body 8 provided by a block moulded from synthetic plastic material and formed to fit externally of the said first arm 1 and within an outer cover 9. As shown in FIG. 2, when the body 8 is in place it is sandwiched between the arm I and the outer cover 9. The outer cover 9 is formed with a peripheral rim 10 within which the body 8 is recessed. The outer cover 9 is fastened to the arm 1 at such rim portion'l0 by conventional means such as for example, by means of rivet, bayonet or projection welding, so that the body member 8 is firmly sandwiched between the cover 9 and the arm 1.

On its inner face the block 8 is formed with a circular recess 11 there is disposed below recess 11 a generally inclined or arcuate recess 12 of elongated form. As the mechanism is viewed externally in its assembled posi tion, i.e. as shown in FIG. 1, the recess 12 opens into the recess 11 between the eight oclock and eleven oclock position so that the recesses communicate at the trailing side of the body 8, considering movement during a latching operation.

A latch member 13 in the form of a partially peripherally toothed circular disc is rotatably mounted in the recess 11, the inner peripheral wall of that recess providing a bearing surface for the latch member 13 which is pivotless. Thus the member 13 turns about its center as shown at 14 and is axially located on the one hand by the inner face of the body 8 and on the other hand by the arm 1. The outer cover 9 not only retains the body 8 and the latch member 13 but also provides a shroud for the latter.

A portion of the periphery of the latch member 13 has a ratchet-toothed formation 13a for engagement by a detent lever 16 which is adapted to act as a pawl and is pivotable within recess 12 on a pivot 17. The pivot 17 is supported inwardly of the lever or pawl 16 in the body 8, from which it projects, for engagement within a locating bore in the arm 1. Outwardly of the pawl 16 the outer end of the pivot 17 is supported in a bore (not shown) in the outer cover 9 which may desirably be made of steel.

A handle lever 18 is mounted pivotally upon a pin 19 as shown in FIG. 1, which is supported inwardly of the lever 18 on the outer face of the cover 9 from which it projects for engagement within a locating bore in the arm 1 which is in alignment with a corresponding bore in the body 8 as will be seen in FIG. 3. A pin 20 secured to the inside face of the lever 18 protrudes through the cover 9 and body 8 slidable in an arcuate slot 21 formed in the cover 9 and in a similar slot 22 formed in the body 8. Pin 20 extends into cam slot 23 formed in the pawl 16 as will be seen in FIG. I. It should be noted that the arcuate slots 21 and 22 are of the same curvature as the path of the driving pin 20 while slot 23 acts as a cam for the driving pin 20. Thus the groove 23 and the pin 20 provide a cam mechanism of the well known inversed type, in which the cam groove 23 is in the follower pawl 16 and the pin 20 which engages this groove is attached to the driving member, namely the lever 18. Rotation of the lever 18 may be replaced by an angular movement of the pawl 16 of lesser magnitude but through a sufficient angle to disengage teeth 16a formed on pawl 16 from the teeth 13a of the latch member 13. The lever 18 is normally urged in a counterclockwise direction, as seen in FIG. 1, by a spring 24 the ends of which are anchored respectively in the holes in the arm 1 and the lever 18 as seen in FIG. 1. The lever 18 is in turn normally urged into engagement with the latch member 13 to hold the back rest in a desired angular position.

As shown in FIG. 1, a pin 25 secured on the inside face of the arm 2 protrudes through the arm 1 and is slidable within an arcuate slot 26 formed therein and extends into a radial slot 27 in the latch member 13. The pin 25 further extends slidablythrough an arcuate slot 28 of the body 8 and an arcuate slot 29 of the cover 9 in slidable relation therewith. It should be noted that the slots 26, 28 and 29 have the same curvature as the path of the driving pin 25 so that the arm 2 may be allowed to rotate through an angle while the radial slot 27 of the latch member 13 provides rotational driven engagement for the member 13 with the arm 2 in cooperation with the pin 25 of the latter. In tilting operation of the arm 2 about the pivot 7, the latch member 13 is rotated about its center 14 within the recess 11 the inner surface of the recess 11 locating and providing a bearing for the latch member. The pin 25 should desirably be disposed as small a distance as is practicable below the center 14 of the latch member 13 so that any loading that may be applied to the back rest by a rear passenger imposes the minimum turning moment on the latch member 13. The absence ofa shaft or spindle for the latch member enables the pin 25 to be located very close to the rotational centre, with the result that very small turning moments are imposed upon the latch member a consequent low loading of the detent lever 16. Thus when the back of the seat is struck by the rear passenger there is resistance against forces which tend to rotate the arm 2, so that the back rest is held in a desired tilted position. As described in the foregoing, the pin 25 is disposed as close below the center 14 as is practicable so that any tendency for the back rest to rotate imposes the minimum turning moment on the latch member 13, the limiting condition being that the construction must be such that a sufficient moment arm is presented to turn the latch member 13, without applying an undue force to the arm 2 during latching and unlatching operations. The low turning moment on the latch member 13 provides correspondingly low loading of the pawl 16. The close disposition to the rotational center 14 is also found benefical in enabling the pin 25 to effect pivotal movement of the back rest through an angle of very fine adjustent relative to the pivot 7 or the seat.

As shown in FIG. 2, the pin 25 is radially enlarged at its free end 2511 to thereby retain its associated parts thereon.

The foregoing is further explained in detail with reference to FIG. 4. In the view, reference characters are given as follows.

M Turning moment on the latch member 13 at pin 25 1 Distance between the pivot 7 and the pin 25 F1 Force applied to the pin 25 to rotate the latch member 13 RI Distance from the center 14 to the pin 25 R2 Radius of the latch member 13 P1 Frictional force to resist against rotational movement of the latch member 13 on the inner or boundary face of the recess 11 P2 Latching force produced by teeth 13a of the latch member 13 and the teeth 16a of the pawl 16 A An angle through which the latch member 13 is so fractionally turned that each tooth of the latch member becomes meshed with the immediately next successive tooth to the pawl 16.

The turning moment M on the latch member 13 is considered to be balanced equally at the pin 25 with the resistance exerted by the forces PI and P2 during latching operation. This is expressed as follows.

The distance RI should desirably be selected through design, as previously described, as small as is practicable so that the minimum of the forces P1 and P2 will sufficiently provide such balancing resistance. Such minimum movement will provide correspondingly low loading of the pawl 16 so that there is substantially no possibility of forces being developed which are capable of damaging the pawl or latch member.

The above calculation will also benefically provide means for fine adjustment of the degree of inclination of the back rest relative to the seat. Thismay be expressed as follows.

B R l /l X A B represents an angle through which the back rest is tilted during the adjusting operation It will be apparent that the pin is beneficially positioned on the opposite side of the'center 14 relative to the pivot 7 so as to effect mechanisms which may permit the tilting of the back rest through a very fine angle.

It will be.concluded from the foregoing that the invention provides a simpler construction for resisting a large loading that may be applied to the back rest by a passenger in the rear passenger seat, the mechanism also being effective for adjusting the degree of inclination of the back rest through an angle of very fine magnitude relative to the seat.

It will be noted that the desired results are obtained primarily through the provision of the circular disc-like latch member 13.

In FIGS. 5 and 6 is shown a second embodiment. Parts which are the same as those shown in FIGS. 1-4 are given the same number in a 200 series. This will reduce unnecessary duplication in the description as to the same parts.

The difference as compared with the first embodiment is based upon the fact that the latch member 213 is additionally formed with a central shaft 214 projecting from the outer face of the member and the block 208 is provided with a corresponding hole 214a at the base of the recess 211 of the block 208. The peripheral surface of the latch member 213 is so slightly spaced from the boundary of the recess 21] that a bearing surface is formed by the latch member which engages the boundary of the recess only when the shaft 214' and/or the pm 225 are damaged or destroyed due to the overloading that may be applied to the back rest by a rear passenger.

This capability for providing a dual system results from the provision of the rotatable circular disc latch member 213. The conventional type of latching mechanism has a sector or segmental gear latching member. This is considered to be disadvantageous in that in case the shaft of the segment gear is damaged mechanism could be completely ruined and the back rest would be tilted through a large angle to thereby cause the passenger to be thrown forwardly out of the seat.

FIGS. 7 to 9 of the drawings show the third embodiment. Parts which are the same as those shown in FIGS. 1 to 4 are given the same number in a 300 series.

The major difference compared with the preceding embodiments is based upon the fact that the first arm 301 is integrally formed with a peripheral rim 350 and i a subarm 351 is fastened to the second arm 302 in spaced and parallel relation therewith in a manner such that part of the first arm 301 and the main latching mechanism are sandwiched between the second arm 302 and the sub arm 351 as best shown in FIG. 8. At least part of the rim 350 faces the peripheral surface of the latch member 313 in so slightly spaced relation that a bearing surface may be formed by the latch member which engages the internal surface of the rim 350 when the shaft 314' and/or the pin 325 are damaged or destroyed by the overloading. As will be seen in FIGS. 8 and 9, within the rim 350 are recessed the latch memher 313 and the lever 316 while the lever 318 is disposed cxternally of the cover plate 309 as best shown in FIG. 9. The pivot 307 is retained in position by a ring 307a in the usual manner. The pin 325 ,is firmly fastened at both ends thereof to the second arm 302 and the sub arm 351 by the usual caulking technique or the like as will be seen in FIG. 8.

. As will be seen ,in FIG. 7, the latch member 313 has an arcuate slot 352 co-centered with the latch member so as to permit the latch member to rotate through an angle for adjusting the degree of tilting of the second arm 302.

I What is claimed is:

l. A hinge fitting for adjustably connecting the seat portion and back rest of a vehicle seat, comprising, in combination, a first .arm adapted to be secured to the seat portion, a second arm adapted to be secured to the back rest, pivot means operatively connecting said arms to permit rotation of said second arm about a pivot axis, a recessed body secured to said first arm provided with a circular recess therein eccentric with respect to said pivot axis, a latch member in the form of a circular disc rotatably arranged within said circular recess with the inner peripheral surface of the recess locating and providing a bearing for said latch member, said latch member having a radial slot therein and a series of locking teeth about a portion of the periphery thereof, pin means carried by said second arm freely slidable within said radial slot, and detent means having a series of teeth engageable with the said locking teeth of said latch member, said circular recess having an opening in the periphery thereof dimensioned to receive said detent means so as to permit engagement of the teeth thereof with the teeth of said latch member.

2. A hinge fitting according to claim 1, wherein the said recessed body is in the form of a main block in which the detent means are mounted.

3. A hinge fitting according to claim 2, wherein the said recessed body is moulded from a synthetic material.

4. A hinge fitting according to claim 2 wherein an outer steel cover is attached to said first arm to thereby retain the said recessed body between the cover and the arm in the manner of a sandwich and accordingly the latch member is also retained in the corresponding body recess.

5. A hinge fitting comprising a pair of arms pivotally connected to each other, a body formed with a recess therein and secured to one of said arms, a rotatable latch member of generally circular disc-like form having an outer peripheral surface at least part of which forms a bearing surface which engages the inner peripheral surface of the recess, the other of said arms having a pin projecting therefrom, the latch member having a radial slot for rotatable driven engagement with said pin, a series of arcuate teeth being formed at least on part of the outer peripheral surface of said latch member, and detent means adapted to retain the latch member in the latching position by engagement of said series of arcuate teeth in said latch member.

6. A hinge fitting comprising a pair of arms pivotally connected to each other. a main body secured to one of said arms and formed with a recess therein, a latch member in the form of a rotatable circular disc positioned in the body recess, said latch member being provided on one side thereof with a central shaft projecting therefrom, said body block being provided with a hole in the base of said recess dimensioned to rotatably receive said central shaft to thereby provide support for the latch member, the periphery of said central shaft being slightly spaced from the inner peripheral surface of the said recess to thereby provide a reserve bearing surface for the latch member usable in a case of damage or destruction of said central shaft, the latch member further being provided with a radial slot for rotatable driven engagement with a pin carried by the other of said arms and detent means adapted to retain the latch member in the latching position.

7. A hinge fitting according to claim 6, wherein the detent means comprises a lever mounted in the block for engagement with the latch member and a cont-actor lever pivotally mounted on said one arm said contactor lever being engageable with said lever.

8. A hinge fitting according to claim 7, wherein the contactor lever is pivoted to the arm which is fastened to the seat frame for release of the latch member from the seat aide.

9. A hinge fitting for adjustably connecting a seat and a back rest comprising a pair of first and second arms pivotally connected to each other. the first arm being fastened to said seat and integrally formed with a pcripheral rim. the second arm being fastened to the back rest. a sub-arm fastened to said second arm in spaced and parallel relation therewith in a manner such that part of the first arm is interposed between the second arm and the sub arm. a latch member in the form of a rotatable circular disc recessed within the rim, said latch member being provided with a central shaft rotatably supported at its both ends by the said second arm and sub arm for normally providing a bearing for the latch member. the periphery of said central shaft being slightly spaced from the internal peripheral surface of the rim to thereby enable said internal surface of the rim to provide another bearing surface reserved for the latch member in case of damage of destruction of the said central shaft. the latch member further being provided with a radial slot for rotatable driven engagement with a pin carried by said second arm. and detent means adapted to retain the latch member in the latching position by engagement therewith. 

1. A hinge fitting for adjustably connecting the seat portion and back rest of a vehicle seat, comprising, in combination, a first arm adapted to be secured to the seat portion, a second arm adapted to be secured to the back rest, pivot means operatively connecting said arms to permit rotation of said second arm about a pivot axis, a recessed body secured to said first arm provided with a circular recess therein eccentric with respect to said pivot axis, a latch member in the form of a circular disc rotatably arranged within said circular recess with the inner peripheral surface of the recess locating and providing a bearing for said latch member, said latch member having a radial slot therein and a series of locking teeth about a portion of the periphery thereof, pin means carried by said second arm freely slidable within said radial slot, and detent means having a series of teeth engageable with the said locking teeth of said latch member, said circular recess having an opening in the periphery thereof dimensioned to receive said detent means so as to permit engagement of the teeth thereof with the teeth of said latch member.
 2. A hinge fitting according to claim 1, wherein the said recessed body is in the form of a main block in which the detent means are mounted.
 3. A hinge fitting according to claim 2, wherein the said recessed body is moulded from a synthetic material.
 4. A hinge fitting according to claim 2 wherein an outer steel cover is attached to said first arm to thereby retain the said recessed body between the cover and the arm in the manner of a sandwich and accordingly the latch member is also retained in the corresponding body recess.
 5. A hinGe fitting comprising a pair of arms pivotally connected to each other, a body formed with a recess therein and secured to one of said arms, a rotatable latch member of generally circular disc-like form having an outer peripheral surface at least part of which forms a bearing surface which engages the inner peripheral surface of the recess, the other of said arms having a pin projecting therefrom, the latch member having a radial slot for rotatable driven engagement with said pin, a series of arcuate teeth being formed at least on part of the outer peripheral surface of said latch member, and detent means adapted to retain the latch member in the latching position by engagement of said series of arcuate teeth in said latch member.
 6. A hinge fitting comprising a pair of arms pivotally connected to each other, a main body secured to one of said arms and formed with a recess therein, a latch member in the form of a rotatable circular disc positioned in the body recess, said latch member being provided on one side thereof with a central shaft projecting therefrom, said body block being provided with a hole in the base of said recess dimensioned to rotatably receive said central shaft to thereby provide support for the latch member, the periphery of said central shaft being slightly spaced from the inner peripheral surface of the said recess to thereby provide a reserve bearing surface for the latch member usable in a case of damage or destruction of said central shaft, the latch member further being provided with a radial slot for rotatable driven engagement with a pin carried by the other of said arms and detent means adapted to retain the latch member in the latching position.
 7. A hinge fitting according to claim 6, wherein the detent means comprises a lever mounted in the block for engagement with the latch member and a contactor lever pivotally mounted on said one arm said contactor lever being engageable with said lever.
 8. A hinge fitting according to claim 7, wherein the contactor lever is pivoted to the arm which is fastened to the seat frame for release of the latch member from the seat aide.
 9. A hinge fitting for adjustably connecting a seat and a back rest comprising a pair of first and second arms pivotally connected to each other, the first arm being fastened to said seat and integrally formed with a peripheral rim, the second arm being fastened to the back rest, a sub-arm fastened to said second arm in spaced and parallel relation therewith in a manner such that part of the first arm is interposed between the second arm and the sub arm, a latch member in the form of a rotatable circular disc recessed within the rim, said latch member being provided with a central shaft rotatably supported at its both ends by the said second arm and sub arm for normally providing a bearing for the latch member, the periphery of said central shaft being slightly spaced from the internal peripheral surface of the rim to thereby enable said internal surface of the rim to provide another bearing surface reserved for the latch member in case of damage of destruction of the said central shaft, the latch member further being provided with a radial slot for rotatable driven engagement with a pin carried by said second arm, and detent means adapted to retain the latch member in the latching position by engagement therewith. 